int fib(int a) {

    if (a == 1 || a == 2) {
        return 1;
    }
    else {
        return fib(a - 1) + fib(a - 2);        
    }

}

int main(void) {

    int a = 21;
    printf("fib(%d) = %d\n", a, fib(a));
    return 0;

}
